The present invention relates to switches, and more particularly to a reversing switch for a microwave coaxial network.
Four-port reversing switches for microwave coaxial networks permit connections between any pair of ports, other than diagonally disposed ports. In certain applications, diagonal connections are also desired, for example, to provide redundancy in a satellite communications network. For example, the additional switch condition can allow a failed section of a network to be bypassed.
Both air-line and strip-line reversing switches are known. Air-line switches tend to be more reliable and less lossy than the alternative strip-line switches. More specifically, the dielectric of the strip-line switch is a source of power loss. Also, the strip-line devices are more sensitive to thermal variations, making it more difficult to match the switch to the incoming and outgoing transmission lines. Thus, performance is less reliable and predictable.
A switch for a redundant network is disclosed in U.S. Pat. No. 4,070,637 to Assal et al. However, this switch is a strip-line device and its configuration is not transferable to air-line switches where isolation of conductors requires distinct cavities. Furthermore, the large number of delicate mechanical connections suggest problems with fabrication and reliability.
What is needed is an air-line microwave coaxial switch which permits diagonal as well as lateral connection. Such a switch should be highly reliable for satellite applications and relatively simple to fabricate.